andees



scribersthereon.

h i UNITED STATES 1 PATENT OFFICE.

GEORGE ANDERS, or BOSTON, MASSACHUSETTS, ASSIGNOR T AMERICAN BELL TELEPHONE COMPANY, OF SAME PLACE.

SWITCH-BOARD FOR TELEPHONE-CIRCUITS.

SPECIFICATION forming part of Letters Patent No; 249,445, dated November 15,1881.

' Application fi1ed Novembe1-9,1880. (Model) To all whom it may concern Beitlknown that LGEo. L. ANDERS, of Boston, county of Suffolk, and State of Massachusetts, have invented a new and useful Improve- 5 ment in switch-Boardsyof which the following [O a telephone-exchange system.

The invention is shown embodied in a central-oflice switchboard of a telephone-exchange in which vertical metal strips arecon- "nected with theditt'erent radiating subscribers circuits, and are traversed by horizontal connecting-strips insulated therefrom, but adapted to beconnected with any of the saidvertical or line strips by the insertion of a suitable connecting-plu g, so that by the employment of two such plugs between two given vertical strips and a horizontal strip the said vertical strips will be connected for the communication of sub- The circuits connected with the vertical strips normally each pass through 2 5 indicating instruments to the ground, and it is, i

of course, necessary to disconnect them from t the ground when connecting them with one another for intercommunication.

My invention consists, partly, in arranging 0 and constructing the parts of the switch-board sothat the operation of inserting the plug to make a connection between a vertical and horizontal strip will also cause the connection of the vertical strip with the ground to be broken.

i t 5 As hereinshown, the verticalstrips are placed behindthehorizontal ones, and aremade movable longitudinally up and down, and normally a rest in their lower position in electrical contact with spring anvil-piecesconnected with the '0 ground, and the plugs employed to make the connection are provided with inclined or camshaped surfaces,which, when they are inserted or placed in position in the switch-board, engage a corresponding part of the vertical strip p 5 and raise it out of contact with the grounded anvil. The lines or subscribers circuits are connected with the vertical strips by flexible connections, sothat their electrical continuity is not broken when the strips are thus moved,

the said connection beingshown as spring-arms resting at their ends upon the tops of the said verticalstrips. A horizontal strip of metal is extended across above the tops of all the vertical strips, just above the point to which they are raisedby the connecting-plugs, so that the central operator, by raising any of the said strips by a handleapplied for that purpose, can

a spring having a tendency to throw them out when unlatched, which may be done by further raising the vertical strip a short distance. This raising of the vertical strip to unlatch the plug may he performed by a strong electromagnet, which may operate on any armature connected with thesaid strip. The said mag net may be charged by a strong local battery,

the circuit of which may be closed by a relay in the subscribers circuit, so that the subscribers, by applying a suitable current on their circuits, canth emselves operate the switch-board to disconnect their circuits from one another, and by thesame operation restore their connection to'the ground.

Figure l is a front view of a switchboard embodying my invention; Fig. 2, a vertical section thereof 5 and Fig. 3, an enlarged section,

'illustratin g the arrangement by which the subscribers are enabled to automatically. disconnect their circuit from one another.

The horizontal connecting-strips a are supported in the end fran1e-work,b,of the switchboard, and are separated by a considerable space from the vertical strips 0, as shown in the sectional views, Figs. 2 and 3. The vertical strips 0 are each to be connected wlth subscribers circuits, the wires of which may be attached by suitable binding-screws to the spring-amid, bearing down upon the upper ends of the said strips, which are movable up and down in their sockets and normally rest on springs e at theirlower ends,the said springs forming continuations of said circuits and being connected with the ground. A

The vertical strips 0 are provided with a series of lifting-shoulders, 2, (shown as the upinclined, as shown at 4, to engage the lifting-...

shoulder 2 of the vertical strip 0, which it is desired to electrically connect with the horizontal strip a, upon which the plug is placed, so that when the plug is inserted it raises the said vertical strip out of contact with the correspondin g spring,e, and thus removes theground at that point from the circuit connected with the said vertical strip at the same time that it makes an electrical connection between the horizontal and vertical strips, as shown in Fig.

.1, where two vertical strips are connected with the same horizontal strip by the plugs t, so that the subscribers on the connected circuits are in communication with one another.

A horizontal strip, 70, insulated from the other portions of the switch-board, is extended across above the upper ends of the vertical or line strips 0, which are provided with liftinghandles 1% at their lower ends, to enable the operator to raise them until they are brought into electrical contact with the said horizontal strip is, which may be called a telephonestrip, as it is intended to be connected to the ground through telephonic instruments of any usual vkind. By this arrangement the centraloffice operator, when a signal is received from a subscribers circuit, by merelyraising the handle at and strip 0, connected with the said *aycircuit, into contact with the telephone-strip k,

is at once placed in telephonic communication with the subscriber who has signaled, the said circuit, being by this operation switched from its ground-connection through the spring 6 to a ground through the telephonic instrument connectedwith the strip k, as shown at the right hand in'Fig. 1. The telephone-strip k is placed at such a height above the ends of the strips 0 that the strips are not raised a sutficient distance by the insertion of the plugs i to come in contact with the said strip k, as clearly shown in the drawings.

In Fig. 3 the pin g is shown as provided with a latch or hook, 5, and with a withdrawingspring, a, having a tendency to throw the plug off the strips,except when held therein by the engagement of the lifting-shoulder 2 of the vertical strip 0 with the latch 5, the said strip being lifted, as before described, by the inclined ends 4 of the plug, and, after the latch 5 thereof has passed, falling into engagement therewith, to thus hold the plug inserted and the vertical strip itself connected with the horizontal one and broken from its ground-connection at e, V lf the strip 0 beraised sufficiently to disengage the latch 5, the plug 2' will be-thrown out by the spring a, to thus disconnect the said strip 0 from the horizontal connecting-strip a and allowit to fall to its normal position in connection with the grounded spring 6. This may be done automatically by the subscribers when they have finished their communication,

thestrips 0 being provided for this purpose with armatures p, to be attracted by electromagnets r, (shown in Fig. 3,) the said magnets being either placed in the subscribers circuits erated by the subscribers for that purpose, or preferably being in a local circuit controlled by a relay in the subscribers circuit. In the latter plan one battery could be used to actuate all the strips 0, to release the plugs i, the magnets 1' being in normally-open branches of the said battery-circuit, any of which would be closed by the operation of the relays before mentioned. I

It is obvious that the shape of the strips and plugs may be greatly varied without departing from my invention-as, for example, the lifting-shoulders, instead of being the upper edges of holes formed in the vertical strips, maybe pins or other projections extended from the main portion of the said strips, or both sets amLm-agnetized by currents thrown on or genof strips may be provided with corresponding "7 holes, preferably circular, and cylindrical plugs maybe used having conical points to bring the holes of the vertical strips which are normally below up into line with those of the horizontal strips when the said plugs are inserted.

By making one of the sets of strips movable in the frame-work relative to the other the plugs are more readily inserted and form a more certain electrical contact than if both sets of strips are rigid, in which case the plugsockets have to be placed in exact relative position, or the plugs will not operate satisfactorily.

The plugsz' are shown as also adapted to enable the central operator to throw his telephonic instrument into communication with two subscribers, who may be 'connectedtogether without breaking their connection, for the purpose of listening to see it"their communication has ended. For this purpose an additional incline or cam, 6, is made in this plug, so that by merely pushing the plug farther in toward the board the vertical or line strip is raised into connection with the telephone-strip 70 without breaking the connection through the plug between the horizontal or connecting strip and the line-strip.

It is obvious that when the automatic disengaging device shown in Fig. 3 is employed the central operator will not have to listen, except when the subscriber may have neglected to operate the said disengaging device on completing their communication, in which case it sired.

might. be desirable for the central operator, when-it was observedthat the connection was continued for too long atime, to listen or speak before breaking the connection.

The telephone-strip k may also have connected with it an apparatus for operating the signals on the subscribers circuit, shown as a battery, B, and suitable keys, r, so that by raising any of the line-strips a into connection with the said telephone-strip, and by causing the circuit to pass therefrom through the said i battery and keys, the subscribers station on the circuit connected with the said raised linestrip may be signaled by properly manipulatin g the said keys 4*. ,A switch, 8, is used to bringthe telephonic instrument or signaling battery and keys into circuit with the strip k, as de- I do not herein broadly claim the combination of a series of movable line-strips with a telephone-strip common to all of them, and adapted to be connected with any of the said line-strips by the proper movement thereof, as

this was not invented by me.

I claim-- y 1. In a switch-board, the connecting-strips combined with line-strips crossing said connecting-strips, but insulated therefrom, and conductors to ground normally in contact, as explained, with said line-strips, and plugs, as indicated, operating by the same movement to connect the desired line-strips and connecting-strips with each other, and to break the connection of the line-strips to ground, substantially as described.

2. In a switch-board, a series of line'strips 3 connected with the subscribers circuits, anda series of connecting-strips to form an electrical connection between any two of the said line-strips, combined with a connector to elecnector, and thereby disconnect the horizontal and line "strips, substantially as and for the purpose described.

3. In aswitch-board, a series of line-strips scribing witnesses.

to be connected with subscribers circuits, and a series of connecting-strips crossing the said line-strips, the strips of one series being made movable in the frame-work, in combination with connecting-plugs adapted to be shifted to different parts of the board independently of said strips, for establishing electrical communication between the strips of the two series, substantially as described.

4. The connecting-strips and a telephonestrip combined with line-strips and plugs or connectors, constructed and operating substantially as described, so that the line-strips can be electrically connected with the telephone-strip by moving the plugs or connectors whichmake the connections'between the line and connecting strips, and without altering or reversing such connections, substantially as described. y

5'. In a switch-board, aseries of horizontal connecting-strips and a series of vertical linestrips, movable longitudinally and normally resting in contact with grounded anvils, combined with connecting-plugs, provided with withdrawing-springs and with latches to be engaged by the vertical strips when the said plugs are inserted, and electro-magnets to opcrate on armatures connected with said strips to move them out of engagement with the said I latches, and allow the plugs to be thrown out from the switch-board by their withdrawingsprings, substantially as and for the purpose the action of said plugs in inserting the same,

and a second series of strips crossing the movable strips at right angles, substantially as de:

scribed.

In testimony whereof I have signed my name to this specification in the presence of two sub- GEOBGE LEE ANDERS.

Witnesses:

J os. P. LIVERMORE, L. F. Comics. 

